Known in the art are hand-held units for manually applying an adhesive layer onto the surface of an article. Also known are automatic motor-driven units in which the adhesive layer is automatically applied onto the surface of an article driven by rollers through the automatic unit.
In a class of hand-held units known as hand waxers, a block of solid wax is placed in the unit and an electrical heater in the unit melts the wax to enable it to be applied in a hot, melted state onto the intended surface to be coated. These hand waxers include chambers which receive the solid block of wax and which form reservoirs for the liquid wax after it is melted. When the supply of electrical current to the heater is turned off, the wax becomes solid and requires subsequent heating in order to be liquified. The hand waxers require a source of electrical current and include an electrical cable for attachment to the power source and a switch to turn the electrical heater on and off. The hand waxers include a housing with an elongated handle thermally isolated from the wax reservoir so that the hand waxer can be comfortably held by the user without contacting hot parts of the hand waxer. The handle extends perpendicularly to the roller and the hand waxer is moved in the longitudinal direction of the handle. The coating roller of the hand waxer is exposed at the lower surface of the housing of the hand waxer and the reservoir is placed above the roller so that it can supply melted wax to the roller for application onto the surface to be coated. When not in use, the housing of the hand waxer is supported in a holding stand which securely supports the hand waxer and conceals the coating roller.
Also known in the art are glue bottles with self-contained applicators usually in the form a soft pad on top of the glue bottle. The adhesive contained in the glue bottle is supplied to the pad which is pressed on the surface to apply a coating of adhesive thereon. In another form of glue bottle, a spherical or small plastic roller is disposed at the tip of the bottle. These units are not refillable and are intended as spot applicators which are discarded when empty. In contrast with the hand waxers, the glue bottles do not apply a uniform thickness layer with precision on the surface of the article, but rather apply bumpy and uneven amounts of adhesive which can even soak through the article, particularly when it is made of relatively thin paper. The width of the coating layer is insignificant compared to the width of the layer applied by the hand waxers. The demand in the industry is for application of a wide, precision coating for mounting or adhering the adhesively coated surface to other surfaces.
In the case of automatic adhesive applicators, these are of greater size and are intended to be placed on a table top for application of the liquid adhesive generally over the entire width of a sheet of material. The automatic adhesive applicators employ a motor drive to rotate the coating roller and a counter roller and in operation the material is fed between the rollers and advanced therethrough, so that the material is provided with an adhesive coating on the surface thereof which comes into contact with the coating roller. The motor drive is usually provided by an electrical motor and an electrical power source supplies the drive of the motor as well as the energy to the heating means which melts the wax placed in a reservoir adjacent to the coating roller.
Also known in the art are gluers which are similar to the automatic wax coaters, except that they contain a tank for liquid adhesive which must be removed after each day of use as otherwise the adhesive will solidify.